The present invention relates to a brake hydraulic pressure controller for a vehicle comprising a pump for refluxing a brake fluid to a master cylinder, an electric motor which operates to drive the pump by way of power supply from a battery, and a control unit for controlling an energization amount to the electric motor by using an energization duty factor predetermined in accordance with the voltage of the battery.
Such a brake hydraulic pressure controller for a vehicle is known from the Unexamined Japanese Patent Application Publication No. 2001-71877.
The above-mentioned brake hydraulic pressure controller for a vehicle performs duty control of the energization amount to the electric motor in accordance with a variation in the battery voltage to reduce the operation sound while limiting the rotation speeds of the electric motor and the pumps so that they will not exceed the necessary values. While a starting torque is necessary to start an electric motor, the starting torque necessary to start the electric motor may not be obtained in the above-mentioned brake hydraulic pressure controller for a vehicle. Conversely, in case a duty factor is determined considering also the start of an electric motor, the steady rotation speed of the electric motor becomes higher than necessary.